Help I'm hopeless

I'm in a relationship where I am starting to feel like it's going nowhere. I don't feel as attracted to my boyfriend as I did when we first started dating, and when we kiss it's like there's no spark. He is a incredible, amazing, smart guy who cares and is kinda a big softie. We get along really well, and we have the same sense of humor.But, when it comes to sex it doesn't work out. It's like when ever we do go to have sex it just seems like we are "trying" to have sex. Reddit, what do I do?A couple months back I posted about how I was really attracted to a coworker, who dropped hints that liked me back, but he was with another guy. I think I'm not over him.